Here's a little something I've been working on for the past few days. It uses a couple (ugly) hacks to show streaming video from demoscene.tv as a screensaver.
Download is here: http://dtv.phatcode.net/
Make sure you read the readme, otherwise I can almost guarantee it won't work for you. Also, if you've got at least a 1Mb net connection, I recommend choosing an HQ relay for better quality.